/Engine/Source/Editor/UnrealEd/Public/Kismet2/BlueprintEditorUtils.h
Find the interface Guid for a graph if it exists.
static [FGuid](API\Runtime\Core\Misc\FGuid) FindInterfaceGraphGuid ( const [FName](API\Runtime\Core\UObject\FName) & GraphName, const [UClass](API\Runtime\CoreUObject\UObject\UClass) * InterfaceClass )